The world No. 3 has been on a roll, with wins in Wimbledon and Cincinnati. (AP)

Simona Halep woke up on Sunday morning just five points short of overtaking Karolina Pliskova’s spot atop the WTA Rankings. All the Romanian needed to become No. 1 in the world for the first time was a win over Wimbledon champion Garbine Muguruza.

But in just 56 minutes, Muguruza dashed Halep’s hopes with a 6-1, 6-0 shellacking, largely in part to her unrelenting groundstroke depth.

When you think of the biggest weapons in tennis, it is easy to point to specific shots. In the women’s game, one may think of Serena Williams and Pliskova’s serves, for example, or Halep’s backhand is among the very best in the sport. But few people think about depth, which was Muguruza’s key weapon in a virtually spotless performance.

Take this moment in the second set, when the Spaniard faced a break point:

It is rare that anyone will be able to regain control of a rally after hitting a 76 m.p.h. second serve against one of the best baseliners in the sport. Yet Muguruza hit all seven of the groundstrokes past the service line, with three landing within mere inches of the baseline.

How does that help Muguruza?

Generally, hitting the ball deep in the court gives your opponent two options. They can give up their baseline and play from a position of relative weakness, or take a tough ball on the rise.

Backing up makes it tougher to be aggressive and increases the likelihood of a player striking the ball off of their back foot, which typically leads to a more defensive ball. Attempting to hit on the rise is a greater risk due to the more difficult timing involved. 

Throughout the final in Cincinnati, Halep—one of the best defensive players in women’s tennis—generally tried to match Muguruza’s aggression, which backfired because of the Spaniard’s consistent depth. Halep hit many balls into the net, especially on her forehand wing, in an attempt to be more aggressive. But many of those shots came from defensive positions.

Even when Halep did come out on top while looking to control a point, it took a series of excellent shots to do so because Muguruza almost never dropped a ball short.

As Halep admitted after the match, she did not play her best tennis. But much of the credit for that belongs to Muguruza, who never gave her opponent much of a chance with her laser-like deep groundstrokes. 

Andrew Eichenholz is a coach at the USTA Billie Jean King National Tennis Center in Flushing Meadows, NY, and has coached the Stony Brook University women's tennis team.